Autoignition of n-Decane under Elevated Pressure and Low-to-Intermediate Temperature Conditions

An experimental investigation of the autoignition for various n-decane/oxidizer mixtures is conducted using a rapid compression machine, in the range of equivalence ratios of ϕ=0.5–2.2, dilution molar ratios of N2/(O2 + N2) = 0.79–0.95, compressed gas pressures of PC=7–30 bar, and compressed gas temperatures of TC=635–770 K. The current experiments span a temperature range not fully investigated in previous autoignition studies on n-decane. Two-stage ignition, characteristic of large hydrocarbons, is observed over the entire range of conditions investigated, as demonstrated in the plots of raw experimental pressure traces. In addition, experimental results reveal the sensitivity of the first-stage and total ignition delays to variations in fuel and oxygen mole fractions, pressure, and temperature. Predictability of two kinetic mechanisms is compared against the present data. Discrepancies are noted and discussed, which are of direct relevance for further improvement of kinetic models of n-decane at conditions of elevatedpressures and low-to-intermediatetemperatures.